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Chemical Bond II: Molecular Orbitals
Published in Franco Battaglia, Thomas F. George, Understanding Molecules, 2018
Franco Battaglia, Thomas F. George
Unlike the hydrocarbons lacking a benzene ring (aliphatic hydrocarbons), aromatic hydrocarbons are more stable, and the chemical behavior of the two classes (and their compounds) is quite distinct. For instance, whereas it is relatively easy to break the carbon-carbon double bond in ethylene and transform the molecule into ethane by hydrogen addition: C2H2+H2→C2H6,
The Petrochemical Industry
Published in James G. Speight, Handbook of Petrochemical Processes, 2019
An aliphatic petrochemical compound is an organic compound that has an open chain of carbon atoms, be it normal (straight), e.g., n-pentane (CH3CH2CH2CH2CH3) or branched, e.g., isopentane [2-methylbutane, CH3CH2CH(CH3)CH3]. The unsaturated compounds, olefins, include important starting materials such as ethylene (CH2=CH2), propylene (CH3·CH=CH2), butene-1 (CH3CH2CH2=CH2), isobutene (2-methylpropene [CH3(CH3)C=CH2]), and butadiene (CH2=CHCH=CH2).
Enhanced Bioremediation of Petroleum Hydrocarbons Using Microbial Electrochemical Technology
Published in Sonia M. Tiquia-Arashiro, Deepak Pant, Microbial Electrochemical Technologies, 2020
Huan Wang, Lu Lu, Zhiyong Jason Ren
Petroleum hydrocarbons are hydrocarbons derived from crude oil (or petroleum products) and popular products including oil, gasoline, diesel fuels, lubricating oil, paraffin wax and asphalt (Altgelt 2016). The major hydrocarbon components are nonpolar fractions that were generally divided into two groups: aliphatic hydrocarbons and aromatic hydrocarbons. Aliphatics mainly include alkanes, alkenes and cycloalkanes. Aromatics have one or more benzene rings as part of their structure, such as benzene, toluene, ethylbenzene, xylenes (BTEX) and polycyclic aromatic hydrocarbons (PAHs) (Speight 2014). Some products may also have polar groups containing sulfur, nitrogen and naphthenic acids.
Late Jurassic Safer Salt Member in the Al-Jawf sub-basin of NW Sabatayn Basin, Yemen: geochemical evaluation of organic-rich oil-source rock potential
Published in Petroleum Science and Technology, 2019
Mohammed Hail Hakimi, Abdulwahab S. Alaug, Hussain J. Al Faifi, Gamal A. Alramisy, Aref A. Lashin
Three powdered samples were extracted using a mixture of dichloromethane (DCM) and methanol (CH3OH) for 72 h using a Soxhlet apparatus and then were fractionated into hydrocarbons (aliphatic and aromatic) and non-hydrocarbon (polar) in order using liquid column chromatography. The aliphatic fraction was analyzed using gas chromatograph (GC) and gas chromatography–mass spectrometry (GC–MS) instruments. A flame ionization detector (FID) was used for Gas chromatograph (GC) with AMS-92 column, temperature programed from 70 to 270 °C at a rate of 3 °C/min, and then held for 20 min at 290 °C. A Finnegan 4000 mass spectrometer is attached directly to the ion source using a programed temperature range of 60–300 °C at a rate of 3 °C/min, and then held for 20 min at 300 °C. In addition, eight (8) cutting samples crushed to a grain size of 2 to 3 mm and then were prepared for vitrinite reflectance (%VRo) measurements under reflected light microscopy and oil immersion using a Zeiss microscope and Leitz Orthoplan/MPV photometry system. An interactive computer program is used to calculate and plot the populations of the mean vitrinite reflectance (%VRo) data reflectances.
Catalytic fast pyrolysis of sugarcane bagasse pith with HZSM-5 catalyst using tandem micro-reactor-GC-MS
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2018
Payam Ghorbannezhad, Mohammadreza Dehghani Firouzabadi, Ali Ghasemian
The biomass thermal degradation mainly composed of complex mixtures of organic compounds. With regards to their functional groups, these compounds can be classified into five groups: 1) aliphatic, 2) aromatics, 3) oxygen containing compounds, 4) nitrogen containing compounds, and 5) polycyclic compounds. Aliphatics were mainly composed of linear and cyclic alkanes, alkenes, and their derivatives such as cyclodecane, hexanes, cyclohexanes. Aromatics were phenols, benzenes, furans, and their derivatives. Oxygen containing compounds contained aldehydes, ketones, esters, and carboxylic acids. Amines amides and nitriles such as propanamides, methylpyrimidines, benzonitrile, and hydoxymetheyl imidazole were identified as nitrogenated compounds. The major chemicals from pyrolysis of lignocellulosic biomass are acetic acid, furfural, hydroxymethyl furfural (HMF) from hemicellulose; levoglucosan and hydroxyacetaldhyde from cellulose; and guaiacol, 2,6-dimethoxyphenols, catechols, syringols, phenol, oxygenated aromatic, alkyl-phenol, and methanol from lignin (Wild 2011). Therefore, the pyrolysis products derived from hemicellulose and lignin from sugarcane bagasse pith were classified into three categories; carboxylic acids (sum of acetic acid, formic acid, and propionic acid), furfural (sum of furfural and HMF), and phenolic compounds (sum of methoxyphenols, phenol, cresol, eugenol, 2,6-dimethoxy-4(2–4-propylphenol, vanilline, hydroxybenzaldhyde, methoxyhydroquinones, ethylphenols). Figure 2 illustrated a typical Py-GC-MS distribution products derived from hemicellulose and lignin of sugarcane bagasse pith. No pyrolytic products were detected by GC-MS when set the pyrolysis temperature was lower than 400°C. When the set temperature was higher than 400°C, pyrolysis products were detectable under either pyrolysis time.
Effects of community-accessible biochar and compost on diesel-contaminated soil
Published in Bioremediation Journal, 2019
Olivia Chitayat Uyizeye, Rachel K. Thiet, Melissa A. Knorr
Hydrocarbons range in their level of toxicity. Some hydrocarbons, including polycyclic aromatic hydrocarbons (PAH) and benzene, are carcinogenic to both animals and humans (Abdel-Shafy and Mansour 2016; Agency for Toxic Substances and Disease Registry (ATSDR) 2016; dos Santos and Maranho 2018). Aromatics, organic compounds in which the carbon atoms form a ring, are generally more toxic than aliphatics, organic compounds in which the carbon atoms form open chains (Interstate Technology Regulatory Council (ITRC) 2014; von Oettingen 1942). Due to petroleum pollution’s global dimension and environmental impact, remediation practitioners must consider long-term ecosystem functioning and community-accessibility of proposed techniques (Frederick and Egan 1994; Singh et al. 2017). Some approaches to petroleum remediation are expensive and energy intensive, including incineration, soil washing, and soil vapor extraction (Kujat 1999; Lim et al. 2016). In 2009, the US EPA Office of Land and Emergency Management established a policy on Principles for Greener Cleanups. This policy supports remediation techniques that reduce their environmental footprint and set a platform for land reuse (Lim et al. 2016; US EPA 2016). One strategy primed to reach these goals is bioremediation, the use of plants, microorganisms, and other soil inhabitants to degrade, remove, or otherwise control a contaminant (Chawla et al. 2013; Cook and Hesterberg 2013; dos Santos and Maranho 2018). Studies have identified bacteria, archaea, fungi, protozoa, viruses, and algae among the ranks of microbial TPH degraders (Juwarkar et al. 2010; Varjani and Upasani 2017). Bioremediation provides potential to remediate sites while enhancing soil properties that support soil organismal and plant communities, as well as provides a positive esthetic for the surrounding human population (Chawla et al. 2013; Sleegers 2010). Bioremediation can also remediate a site at a lower cost, often 80–90% less than that of engineered techniques, increasing its potential widespread implementation (Chen et al. 2015; Megharaj et al. 2011; Singh et al. 2017; Stephenson and Black 2014).